target/102125 - alternative memcpy folding improvement

target/102125 - alternative memcpy folding improvement

The following extends the heuristical memcpy folding path with the
ability to use misaligned accesses on strict-alignment targets just
like the size-based path does.  That avoids regressing the following
testcase on arm

    uint64_t bar64(const uint8_t *rData1)
    {
        uint64_t buffer;
        memcpy(&buffer, rData1, sizeof(buffer));
        return buffer;
    }

when r12-3482-g5f6a6c91d7c592 is reverted.

2022-03-23  Richard Biener  <rguenther@suse.de>

	PR target/102125
	* gimple-fold.cc (gimple_fold_builtin_memory_op): Allow the
	use of movmisalign when either the source or destination
	decl is properly aligned.